CONCHIFERA. 
It) I 
Genus 51.—ERYCINA.— Lamarck. 
Generic Character. — Transverse, subinequilateral, equivalve, 
rarely gaping; with two primary teeth, unequal, diverging, 
with a pit interposing; lateral teeth two, oblong, compressed, 
short, and inserted ; ligament internal, situated in a pit. 
Erycina striata. — The Striated Erycina. 
Plate XC. fig. 21. 
Yellowish-green, with strong transverse striie. One inch 
long. Inhabits the Indian ocean. 
Genus 52—CRASSATELLA. 
Generic Character .—Inequilateral, suborbicular or transverse, 
close ; primary teeth somewhat divergent, with a hollow at the 
side; no lateral teeth, nor obsolete ones; ligament internal, 
inserted into a pit in the hinge. 
Crassatella Kingicola. — The King’s Island Crassatella. 
Plate XCI. fig. 1. 
Ovate, orbicular; yellowish-white; with obsolete rays; very 
minutely striated transversely ; the umbones somewhat plicated. 
Two inches long. Inhabits the sea at King’s Island, New 
Holland. 
Genus 53.—LIGULA.— Montagu. 
Generic Character. —Equivalve, with a broad transverse tooth 
in each valve, projecting inwards, furnished with a pit for the 
reception of the cartilage, and in some species a minute tooth. 
Ligula prcetenuis .— The Very Thin Ligula. 
Plate XCI. fig. 2. 
Oval, flat, thin, brittle; a little gaping; valves with a single, 
spoon-like tooth in each, projecting horizontally inwards ; white, 
with a few concentric striie. One inch broad. Inhabits the 
British seas. 
*** Ligament internal; shell gaping at the sides. 
Genus 54.—MACTRA.— Linnaeus. 
Generic Character. —Transverse, inequilateral, subtrigonal; 
2 r 3 
